Magnesium base alloy



Patented June 16, 1942 2,286,866 MAGNESIUM BASE ALLOY John C. McDonald, Midland, Mich., assignor to The Dow Chemical Company, Midland, Mich., a corporation of Michigan No Drawing. Application December 23, 1940,

Serial 100,371,370,

. 2 Claims.

The invention relates to magnesium base alloys and more cparticularly concerns an alloy of this nature having a high degree of formability assomanifest over the entire range of composition indicated, I have found that, in generaL'when the 1 alloy contains from about 0.1 to 0.7 per cent of ciated with other desirable physical properties,

cerium, 0.05 to 0.5 per cent of calcium, from 3- Other objects and advantages will be apparent as the description of the invention proceeds. v

My invention resides in the discovery that a magnesium base alloy containing from about 0.01 to 1 per cent of cerium, 0.01 to 1 per cent of calcium, 1 to 12 per cent of cadmium, and from about 0.01 to 3 per cent of manganese possesses the aforementioned improved properties. The term magnesium used herein and in the appended claims is intended to' include magnesium 60 containing the ordinary impurities that are found in the commercially pure metal, such as traces of iron, copper, nickel, and silicon. While the properties of highly improved tensile and yield strengths coupled with excellent formability are such as excellent'tensile and yield strengths. 5 to 7 per cent of cadmium, and from 1.5 to 2.5

Magnesium base alloys are being widely used per cent of manganese, it possesses the most-dein the structural arts where a light weightmetal sirable combination of properties. A particuis highly desirable, such as for use in making castlarly desirable alloy composition contains about ings, forgings, and the like. However, the use of 0.4 per cent of cerium, 0.15,per cent of calcium, 5 these alloysin the rolled form to make 'sheet metal 10 per cent of cadmium, and 2 per cent of manarticles requiring forming operations, such as ganese, the balance being magnesium. bending, drawing, and the like, has not pro- The following table listing some of the propergressed as rapidly due to the fact that, in general, ties of rolled sheet metal made from my new alloys having goodformability or ductility perquintary alloy and comparing these properties mitting relatively sharp bends to be made without with those of closely related quaternary alloys i1- the article developing external cracks, usually lustrates the improvement in tensile and yield have inferior characteristics as regards their tenstrengths of my new alloy over that of the related sile and yield strengths. commercial alloys. v

It is, accordingly, the principal object of the In the table the per cent elongation is to be invention to provide a magnesium base alloy regarded as a measure of the ductility or formwhich can be made into rolled sheet and the like ability'of the alloy.

. Table N z i urglgy lgg ag t I Annealed- Cold rolled Percent Yield .Tensile Yield Tensile Ce Ca Cd Mn elongation strength in strengthin strengthin strength'in in2inches lbs/sq. in. lbalsq. in. I lbs./sq. in. lbs/sq. in.

possessing a high degree of ductility or form- The properties set forth above under the term ability at ordinary temperatures permitting it to annealed" were obtained by first rolling specibe sharply bent, drawn; or otherwise shaped, mens ata temperature of 600 Rand thereafter while also having highly improved tensile and annealing them at various temperatures in a yield strengths. 40 range of from 400 to 800 F. The properties selected for the'table werethose of the annealed specimens which exhibited the maximum elongation. The properties set forth under the term cold rolled were obtained by subjecting specimens of the alloys, which had first been hot rolled at a temperature of 600 F., to additional rolling in the cold state. The properties selected for the table were those of the cold rolled specimens which exhibited the greatest tensile and yield strengths, while having at least a 1 per cent elongation in 2 inches. v

A comparison of the properties listed in the table shows that the tensile and yieldstrengths of my new alloy are superior to those of closely related alloys, while the ductility or formability as represented by the per cent elongation is also of a high order. A corresponding improvement is exhibited throughout the composition range of h the alloying ingredients indicated.

While the new alloy is most useful in wrought form, due to its formability characteristics it may also be suitably used in making castings, extruded forms, and the like.

The new alloy may be compounded by any of the methods usually employed for melting and alloying metals with magnesium,such as by adding the alloying ingredients singly or jointly to a bath of molten magnesium which is preferably protected from oxidation by a suitable flux. The flux should be substantially free from magnesium chloride it the calcium content of the alloy is above 0.3 per cent. In those instances where an alloy is to be compounded containing less than 0.3 per cent of calcium, magnesium chloride 'may be present in the flux, but in this case it is preferable -to add the calcium last and without too much stirring and agitation in order to prevent v loss of calcium into the flux. Cerium maybe metal since the alloying efliciency is not always 100 per cent and some loss may be incurred.

It is to be understood that the invention is not limited to the specific composition herein described, but may take other forms without departing 1mm the scope of the invention.

I claim:

1. A magnesium base alloy containing from about 0.1 to 0.! per cent or cerium, from 0.05 to 0.5 per cent of calcium, from 3 to 7 per cent of cadmium, and from-about 1.5 to 2.5 per cent 01' manganese, the balance being magnesium.

2. A magnesium base alloy containing 0.4 per cent or cerium, 0.15 per cent of calcium, 5 per cent of cadmium, and 2 per cent 01' manganese, the balance being magnesium some c. ucnomm. 

